The present invention relates to power supply techniques for a power system, and more particularly to techniques effective for application to power supply by a parallel power system and an electronic apparatus using the parallel power system.
A parallel power system is used by various reasons and objectives. For example, such reasons include the case wherein a large capacity power system is configured by using power source circuits of small capacity, the case wherein the number of power source circuits are increased or reduced when necessary, the case wherein a redundancy structure is incorporated to improve reliability, and other cases.
As a power system of this type, a parallel power system is disclosed, for example, in JP-A-9-93929, which system supplies a d.c. power to a load by using a plurality of AC-DC switching power sources or DC-DC converter power sources of a redundancy structure.
The invention provides a parallel power system capable of flexibly changing output currents and the number of channels when a specification change of the parallel power system to be caused by a design change of an electronic circuit occurs. The invention can considerably reduce the cost and shorten the time for the change of the parallel power system. The invention can avoid discarding an electronic circuit equipped with the parallel power system so that the lifetime of the electronic apparatus can be prolonged.
According to an embodiment of the invention, a parallel power system is provided in which a plurality of power source circuits and one or plural electronic circuits are mounted on a back board and desired ones of power outputs of the plurality of power source circuits are connected in parallel to supply power to the electronic circuit. The back board has a plurality of feeder lines for independently supplying each power output of the plurality of power source circuits to the electronic circuit. The electronic circuit has power source lines for connecting in parallel desired ones of the feeder lines of the back board. If a plurality of power source circuits are divided into groups for different voltage channels, the electronic circuit has independent power source lines in correspondence with respective groups.
If each power source circuit has a function of outputting a control signal for controlling a parallel operation, the back board has a plurality of signal lines for independently transferring each control signal for the power source circuits to the electronic circuit. The electronic circuit has control lines for connecting in parallel desired ones of the signal lines of the back board. The electronic circuit may be structured by using a plurality of circuit boards.
Another embodiment of the invention provides a parallel power system for supplying power to the electronic circuit by connecting in parallel of desired ones of the power source circuits by using a feeder bus in place of the back board.
Another embodiment of the invention provides a parallel power system for supplying power to the electronic circuit by connecting in parallel of desired ones of the power source circuits by providing the electronic circuit with a parallel connection mechanism for connecting in parallel desired ones of the power source circuits.